The invention relates to an adjusting device for a vehicle parking brake for the automatic compensation of cable stand elongations, and more particularly to such an adjusting device having a small number of parts and high operational reliability, even when dirty.
An adjusting device which is to be installed exposed on the underside of the vehicle body for automatically compensating for cable strand elongation in a vehicle parking brake arrangement is disclosed by unpublished Patent Application No. P 3,741,529.8.
In this construction a cable yoke is formed by two yoke elements of identical construction arranged symmetrically and pivotably on a bearing axis. Each yoke element holds a cable strand and are each equipped with a catch tooth forming a bracing element which is retained in engagement with a catch tooth system provided on a U-shaped traction plate by a torsion spring.
The bearing axis which carries the yoke elements is guided slidably by each of its axis ends in a guide slot extending in the tensioning direction of the cable strands, the guide slots being provided in mutually opposite members of the U-shaped traction plate.
A tensioning device which serves for the automatic compensation of elongations which occur in the cable strands has a permanent tendency to slide the bearing axis with the yoke elements in the tensioning direction relative to the traction plate. The tensioning device is equipped for this purpose with a compression spring which is braced against the yoke elements and against the traction plate.
Accordingly, it is an object of the present invention to provide an adjusting device for automatically compensating for cable elongation in a vehicle parking brake arrangement, which has a smaller number of components, and high operational reliability, even in an extremely dirty state.
The adjusting device according to preferred embodiments of the invention advantageously features only a one-piece cable yoke, a bracing element and a catch tooth system, parts which can be structurally designed and arranged in such a way that any jamming caused by dirt particles of the components required to be moved by the tensioning device can be effectively prevented.
The arrangement of the catch tooth system on the circumference of a disc cam mounted on or constructed integrally with a bearing axis of the cable yoke and which is rotated by a torsion spring relative to the bracing element cooperating with the catch tooth system and anchored on the traction plate in order to adjust the cable strands, ensures an automatic cleaning of the dual catch recesses upon the engagement of the bracing element into them. As a result any dirt in the catch recess is then displaced out of the relevant catch recess. It is favorable for this purpose if the catch recesses of the disc cam, which rises steadily at the circumference, are trough-shaped considered in their axial direction, and if the bracing element exhibits a catching part adapted to the cross-sectional form of the catch recesses.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.